The troughs or pans of conventional scraper-chain conveyors, as used in mineral mining operations, are usually composed of a stout floor plate or tray connected between a pair of side walls each with a general sigma-shaped profile. The side walls and the floor plate define upper and lower guide channels in which scrapers of a scraper-chain assembly are guided in a conveying upper run and in a return lower run.
It is known to connect the individual pans together in end-to-end relationship so that the pans can perform certain angular movements in horizontal and vertical planes relative to one another. To achieve this, the pans are connected together at their adjacent ends with connectors such as toggles, threaded bolts or coupling eyes. During operation, gaps can open up at the joints between the floor plates of adjacent pans and fine material can fall though these gaps to build up in the lower run. To avoid this, it is known to provide the floor plates with reduced or stepped end regions which provide mutually overlapping tongues. The floor plate joints can also be formed by providing welded-on strips at the ends of the floor plates. The overlapping tongues at the ends of the floor plates extend perpendicular to the longitudinal axis of the pans over their entire length. It is also known to provide axially extending projections which engage in recesses at the mutually facing ends of the floor plates of the joints to align and centre the pans in vertical and lateral directions (See DE-OS-3903347 and DE-PS-3150459). In these cases the overlapping tongues of the floor plates are provided with rectangular recesses and projections.
During operation, when the scraper-chain assembly is circulated along the pans to transport material loud noises frequently occur when the scrapers impact on the joints between the floor plates or drop into depressions at these joints. This noise is especially prominent when the pans are inclined relative to one another and this is often the case when the pans are laid on anticlines and synclines at the floor of the mine working. When resting on an anticline the upper overlapping tongues of the floor plates which project over the lower overlapping tongues can incline to protrude over the general level of the floor plates to form an impediment to the passage of the scrapers. To counteract this problem it is known to chamfer the overlapping upper tongue-see DE-OS-3903347. This measure does reduce the noise and wear but does not eliminate these undesirable aspects.
An object of the present invention is to provide channel sections or pans for a scraper-chain conveyor, particularly for in-board conveyors with a scraper-chain assembly with one or more chains running along the central region of the conveyor pans, in which the joints of the floor plates of adjacent pans are improved.
Another object is to so construct the joints between floor plates of adjacent pans that there is adequate sealing at all times with the gentlest possible passage by the scrapers without excessive noise even if the pans become inclined relative to one another.